The present invention relates to devices for expanding flexible tubes and similar elastic articles and, more particularly, to a device which may be mechanically, hydraulically, or air activated.
Tube expanding and stretching devices are well known in the prior art. They generally include a plurality of cooperating fingers which are inserted into a flexible tube or elastic article and subsequently spread in relation to one another to expand the tube or article. The spreading of the fingers can be accomplished by a variety of mechanical arrangements which include a direct mechanical cable drive, air or hydraulic cylinder drives, or hand lever drives. In most cases, however, the mechanical arrangements are complex or are not versatile enough to be used with a variety of elastic articles or tubes.
By way of example, there are known in the prior art, stretching devices which include multiple fingers driven by a pedal operated Bowden cable or by a hand operated lever mechanism. The mechanical linkage used to accomplish the spreading of the fingers includes rotating ring and pin arrangements coupled to the hand operated lever or to the Bowden cable drive mechanism. The construction of these devices does not allow for easy replacement or substitution of the particular drive mechanism and the complexity of the finger spreading arrangement invites time-consuming repair and replacement problems.
In other instances, the devices include simple two-finger, hand actuated, fulcrumed lever arrangements which can be easily maintained and repaired. Such devices, however, have limited application since they are not readily adaptable to articles of different size and cannot account for the changes in elasticity of such articles. Since they are hand-held, they are also not easily adaptable to other mechanical driving mechanisms.
Accordingly, the present invention has been developed to overcome the shortcomings of the above disclosed and similar devices and, more particularly, to provide an inexpensive and versatile tube spreading device.